<?php 
$sP1 = date('m-d-Y');
$sP2 = date('m-d-Y', strtotime('+01 month'));
$sP3 = date('m-d-Y', strtotime('+02 month'));
$sP4 = date('m-d-Y', strtotime('+03 month'));
echo $sP1."\n";
echo $sP2."\n";
echo $sP3."\n";
echo $sP4."\n\n\n";

$sP1 = date('m Y');
$sP2 = date('m Y', strtotime(date('M-1-Y').' +01 month'));
$sP3 = date('m Y', strtotime(date('M-1-Y').' +02 month'));
$sP4 = date('m Y', strtotime(date('M-1-Y').' +03 month'));
echo $sP1."\n";
echo $sP2."\n";
echo $sP3."\n";
echo $sP4."\n";
?>

05-31-2012
07-01-2012
07-31-2012
08-31-2012


05 2012
06 2012
07 2012
08 2012